"I knew she had caddied for me before and was friendly with Zach Johnson, and figured she would be good to handle it, and Zach would go easy on her", Kuchar said.
An eagle late in his round catapulted the 2015 Australian Open Champion up the leaderboard, the day reversing an ordinary run of form in his opening three events of the new PGA Tour season.
"If you're not driving it well, this course is extremely hard", said the seven-times PGA Tour victor.
Rickie Fowler ended the day at five under, with Tony Finau at two under and Jordan Spieth struggling at even par alongside Johnson after a wildly inconsistent round.
Among those in the large group at 65 was Abraham Ancer, whose tie for fourth last week in Las Vegas moved him to No.98 in the world, making him the first Mexican golfer to crack the top 100 in the world rankings.
The PGA Tour fall schedule is going strong and players get to enjoy a little time on the beach for this week's Mayakoba Golf Classic in Playa Del Carmen, Mexico.
Also at 65 were Bud Cauley as he returns from a vehicle accident at the Memorial in early June, and defending champion Patton Kizzire, who made back-to-back eagles on the par-5 fifth hole and by holing out on the par-4 sixth. With his normal caddie already holding a scheduling conflict, Kuchar instead hired a local caddie to fill the void. Kuchar's wife was following along in the gallery and carried Johnson's bag the rest of the way.
"I didn't talk too much to Damon, but you could tell it was heat fatigue, heat exhaustion", Kuchar later told reporters.
Kuchar and Johnson live at Sea Island on the Georgia coast.